Plays similarly to Powder, but Powder is a lot more complex, and far more scarier. I've still yet to touch my current play through on Powder, because although i feel very strong so far (in the higher 20s with two roaming well-equipped and well-skilled tame monsters, both high-end golems, IIRC), the situation i'm in calls for some serious strategizing that i lack severely. well... i'm in a big hall-type floor with tons of scary strong monsters (and i mean scary strong; dragons i eat for breakfast) and an active spell cast on me that turns me into a big neon sign for every monster on the floor. and 3 angry gods, one priming for a good Flashfire or something like that.
this on the other hand, plays very simply, and so far the difficulty is only in the fact that more often than not you're faced with monsters far stronger than yours from the get-go. tough luck if you start surrounded by lvl2 monsters and less than five lvl1 in reach (you need to defeat at least five to level up). if you can't level up, you can't beat the monsters. Powder on the other hand, can let you survive situations like that, provided you know a lot of what you can and cannot do with items and whatnot, and that you think out of the box.
i like the "next hit estimate mechanic" in this game though.